Get All Permutations Of A Numpy Array

I have a numpy array [0, 1, 1, 2, 2, 0, 1, ...] which only contains the numbers 0-k. I would like to create a new array that contains the n possible arrays of permutations of 0-k.

Solution 1:

Your a is what combinatorists call a multiset. The sympy library has various routines for working with them.

>>>from sympy.utilities.iterables import multiset_permutations>>>import numpy as np>>>a = np.array([0, 1, 0, 2])>>>for p in multiset_permutations(a):...    p...
[0, 0, 1, 2]
[0, 0, 2, 1]
[0, 1, 0, 2]
[0, 1, 2, 0]
[0, 2, 0, 1]
[0, 2, 1, 0]
[1, 0, 0, 2]
[1, 0, 2, 0]
[1, 2, 0, 0]
[2, 0, 0, 1]
[2, 0, 1, 0]
[2, 1, 0, 0]

Solution 2:

if your permutations fit in the memory, you could store them in a set and thus only get the distinguishable permutations.

from itertools import permutations

a = [0, 1, 0, 2]

perms = set(permutations(a))